sorting brass and bullet question

D

drover

Member
I only compete in local shoots and am not a benchrest shooter with a capital "B", but like everyone else I am looking for an edge.

I have tried sorting brass and bullets by weight and it does seem to give me more consistent groups, but my question is this - just how much variance should be tolerated?

For example let's say the brass on average weights 92 grains, do you sort them to the first decimal point such as 91.8, 91.99, 92.0, 92.1, 92.2, etc and keep each weight segreagated? Or do you separate and segreagate by larger increments such as 92.0 thru 92.4? And I have the same question about bullets, just how much variance do you allow between bullets and still keep them as a lot?

I hope that my question is clear, if not let me know an I will try to re-phrase it for more clarity.

Any thoughts are appreciated.

Thanks in advance - drover
 
Here is a spreadsheet that I made several years ago. Pretty simple - take a random sample of your cases (50 or so) and weigh them. Enter the mass in the spreadsheet, then change the % at the bottom to whatever % of the STD you want. Higher the %, the lower the tolerances. The spreadsheet will tell you which cases to keep and which ones to save for later.

From my little experience - sorting cases does not help with accuracy. I have not used this spreadsheet in 2-3 years. Keep the cases you cull, you might use them again later.

However, there is always that mental part that says "I did this or I did that, therefore I should be shooting good." That mental confidence is worth something. So, if you think it will help - then, by all means, do it - cause it isn't going to hurt to sort your cases by weight.

Stanley
 

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Like Apollo I've tried sorting cases by weight for a BR rifle. I weighed the cases on a calibrated laboratory balance (to -0.1 mg), so there wasn't a question that they weighed what they weighed. The best groups came with the cases mixed together. If you use good bullets weighing them will keep you busy, but otherwise doesn't do anything useful.

One thing that will make a difference is chasing the throat. With some rifles accuracy will fall off slowly so that it's almost unnoticeable, especially if you shoot like I do. My scores/groups slowly dropped off and I could not figure out why, until I checked the throat. When the bullets were seated out to where they liked accuracy returned, until the bullets couldn't be seated in the cases anymore to chase the throat. :(
 
drover said:
For example let's say the brass on average weights 92 grains, do you sort them to the first decimal point such as 91.8, 91.99, 92.0, 92.1, 92.2, etc and keep each weight segreagated? Or do you separate and segreagate by larger increments such as 92.0 thru 92.4? And I have the same question about bullets, just how much variance do you allow between bullets and still keep them as a lot?
Click to expand...
http://blog.sinclairintl.com/2008/12/24/weighing-cases/

Sort them to .1 and you will see a pattern from which you can choose what to use. There is little point in having exact tolerances (like +-.3gr or 3% etc.). Just look at the pattern, take out the oddballs and even out the rest depending on how many cases you have and how many you will load at a time.

If you are sorting new brass some of the weight differences will even out when you prep them and trim after firing.
 
What may make some sense

would be to find the internal volume differences and segregate your cases that way. I believe there can be enough difference in the shape and size of the head part of the cases so as to cause them to be of different weights. Now, the internal capacity, this is a different kettle of fish.

I would do this by recording the weight of the cases individually then fill them with water, weighing the amount of water in there. Weight = space, eh? It is impossible to make ammo that is TOO GOOD. That said, some things we do to try to improve our ammo don't work :( :D.
 
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Thanks for the replies.

Mike, you hit it on the head - yes! I am shooting a 223, not exactly a benchrest caliber but as I mentioned it is for local shoots and it gernerally does well. It is a consistent sub 1'2" rifle which I know doesn't raise anyones attention at a real match but for what we do locally it is sufficient.

I have taken 100 pieces of brass and sorted and weighted them, and as is predicitable the weight variance creates a Bell curve. I have been using the center third of the brass in the Bell curve and doing the same with the bullets. I cannot say that my groups have become smaller but they have become more predicatable, resulting in fewer head-scratchers wondering why a shot was out of the group, whether this is because of an increased confidence factor or the sorting process I really don't know.

It sounds as though I have gone about as far as necessary and that I have
probably reached the point of diminishing returns.

Thanks to each of you for your input, I appreciate it.

drover
 
you probably would see more results from

sorting your bullets by length using a comparitor or Sinclair Nut. Sorting them using that method allows one to end up with more considtent OAL's where the bullet will engage the throat of the barrel.
 
drover said:
Thanks for the replies.

Mike, you hit it on the head - yes! I am shooting a 223, not exactly a benchrest caliber but as I mentioned it is for local shoots and it gernerally does well. It is a consistent sub 1'2" rifle which I know doesn't raise anyones attention at a real match but for what we do locally it is sufficient.

I have taken 100 pieces of brass and sorted and weighted them, and as is predicitable the weight variance creates a Bell curve. I have been using the center third of the brass in the Bell curve and doing the same with the bullets. I cannot say that my groups have become smaller but they have become more predicatable, resulting in fewer head-scratchers wondering why a shot was out of the group, whether this is because of an increased confidence factor or the sorting process I really don't know.

It sounds as though I have gone about as far as necessary and that I have
probably reached the point of diminishing returns.

Thanks to each of you for your input, I appreciate it.

drover
Click to expand...

Just my opinion, understand. But what you are doing is a total waste of time. My guess is that you have a standard SAAMI 223 chamber. If you are going to that much trouble you need a custom chamber reamer. You might be able to set your barrel back a bit and rechamber it to a close fitting chamber. If you have more than 0.002" clearance between a loaded round and the chamber neck diameter, you are wasting your time. Thats just one of the reasons why the real BR rifles shoot so good. Very close fitting cases. Some shoot as close as .0005 total clearance. 0.002 is good enough for me.
Donald
 
Viper* - Thanks for the link, I usually read the Sinclair tech tips it appears as though I missed this one - good read.

Pete, I do use a comparator to establish and check length and also a Sinclair nut and have found them both to be helpful, this particular rifle is sensitive to seating depth, it likes .005 off of the lands for the best accuracy.

Donald, I agree with what you are saying, I have tried neck-sizing only and full length sizing with just a "bump" setback and it shoots best with the F/L and "bump". My current barrel is a SAAMI chamber but it is cut to the minimum side. When this barrel begins to degrade I intend top replace it with a minimum neck/chamber barrel.

I do have my own bench setup at home and use wind-flags and know my conditions here very well and so far the combination I have arrived at is my best (most consistent) accuracy so at this point I am searching for that next step to give me just a little more edge in consistency.

Thanks for all of the thoughts - ideas and thoughts are always welcome, keep them coming.

drover
 
Pete

Am I missing something you measure from base to comparator diameter then seat by the pointy end all you are measuring is difference in bearing surface if the ogive is the same seating depth will not be effected by the measurement your making?No smart sarcasmn intended I'm just not getting what your saying?
Merry Christmas jim
 
Donald said:
The nice part about the 223 is cheap ammo. When you get around to replacing that barrel you might think about a Beggs 220. Yeah, I know, costs a bit more, but you get what you pay for. Besides...we aren't going to be here for ever.

Donald
Click to expand...
 
For what it's worth--a long time ago I learned the 5% rule, from where I
cannot remember, but I have used it for a long time and it seems to be true. It works for bullet and case weight and bullet length, you name it except maybe for powder charges.

In this case, pun intended, if a case is more than 5% heavier than the mean case weight of a given group--save it for another group. So, if the mean weight of your group of 100 cases is 91 grains, then 91 x 1.05 = 95.55 grains and it goes into the heavy box. And, 91 x .95 = 86.45 grains and it goes into the light box.

I know there are people who cull using closer tolerances and there are some who do not cull. This works for me.
 
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